electric and hybrid-electric aircraft · 2019. 8. 7. · keep a320 design + “replace turbine with...

Electric and Hybrid-Electric Aircraft:A pragmatic viewCEC/ICMC Conference 2019, Plenary Talk

23.07.2019 – Connecticut Convention Center

Dr. Mykhaylo Filipenko

Siemens AG – Corporate Technology – eAircraft

Unrestricted © Siemens AG 2019 Dr. Mykhaylo Filipenko Siemens eAircraft

Unrestricted © Siemens AG 2019

July 2019 Corporate Technology

A glimpse into the future of transportation



An Episode of Mythbusters

Focus Topic: Electric Aviation



Agenda

I. (Hybrid-)electric flight (in a nutshell)

II. Mythbusters: Particular Topics

III. Should we invest into (hybrid-)electric?



LiI

on

/LiP

oc

om

me

rcia

lly a

va

ila

ble

MB-E1

Solair 1

Taurus G4

eGenius

E-FAN

E-FAN 1.0

EXTRA 330LE



Siemens eAicraft flight test history

2011

Maiden flights of the DA36 e-Star, world‘s first

hybrid-electric aircraft, and improved eStar 2, with Airbus and Diamond Aircraft

2013 2016

Maiden flight of the record propulsion system SP260D in the Extra 330LE

2016

¼ Megawatt

2018

Maiden flight of the SP70D in the Magnus eFusion Maiden flight of the world’s first two engined serial-hybrid propulsion system



Why do we want to fly electrically?

Maintance,

Insurance, etc.

Crew

15%14% 100%

TCOFuel

20%

Purchase

51%

Total cost of ownership (Bsp.: Boeing 737-800))1

→ Fuel is a main cost driver

ACARE 2050 goals can only be achieved with

disruptive concepts1)

20502040203020202010

→ “Flight-path 2050” of EU requires 90 % reduction of

NOx/CO2 emissions and 75 % noise emissions

Potential by further development of current technologies

Potential with disruptive technologies (e.g. eAircraft)CO

2 E

mis

sio

ns

Year

* IATA technology roadmap, June 2013** eAir: Market studies



Challenge One – Battery

0

5000

10000

15000

20000

25000

30000

35000

Kerosine Li-Ion Li-Air Al-Air ST Al-Air LT LH2

Energy Density of Various Energy Sources in kWh/kg



Extended eAircraft

portfolio

Hybrid Electric Propulsion System

Core eAircraft

portfolio

ACDC

DCAC

DCDC

Storage

Power Distribution Motor1)Generator1)

Turbine / ICE

Propulsion System

Propulsion Unit

• Motor

• Inverter

• Propeller

• Gearbox

Power Generation

• Generator

• Inverter

• Controller

• Turbine/ICE3)

Power Distribution

• Circuit Breaker

• Switches

• Cables

• Connectors

Energy Storage

• Battery Packs

• Converter

• BMS2)

1) E-machines are capable to fulfill “power generation” and/or “propulsion” depending on e.g. mission profile,

requirements and/or mode of operation, 2) Battery Management System (BMS), 3) Internal Combustion Engine (ICE)



Agenda



III. Should we invest into (hybrid-)electric?



Myth 1:

“A hybrid-electric A320 is a good airplane”

Keep A320 Design + “Replace turbine with hybrid-electric drive train” = “Not a good concept”

*Images taken from G. Atanasov: „Energy Efficient Hybrid Propulsion Concept for Twin Turboprop Aircraft“



Hybrid Electric Propulsion System vs. Conventional

ACDC

DCAC

DCDC

Storage

Power Distribution Motor1)Generator1)

Turbine / ICE

Energy Storage

• Battery Packs

• Converter

• BMS2)

Turbine / ICE

Conventional

HEPS

𝜂𝑇 ∙ 𝜂𝐺 ∙ 𝜂𝑃 ∙ෑ

𝑒

𝜂𝑒 < 𝜂𝑇 ∙ 𝜂𝐺 ∙ 𝜂𝑃 𝑚𝑇 +𝑚𝐺 +𝑚𝑃 +

𝑒

𝑚𝑒 > 𝑚𝑇 +𝑚𝐺 +𝑚𝑃

η ~ 80 %

η ~ 97 %η ~ 98 %

η ~ 98 %

η ~ 98 %

η ~ 99 %

η ~ 40 %

η ~ 98 %

η ~ 99 %

η ~ 99 %

η ~ 99 %

η ~ 80 %η ~ 40 %



Myth 2:

“We can have on optimized turbine operation point”

*Images taken from M. Ekwonu et al.: „Modelling and Simulation of Gas Engines Using Aspen HYSYS” and x-engineer.com

Turbine Design Point:

“One Engine Off”

“Take-Off”

“Cruise”~ 2.5 %

~ 1 %

ICE for cars Gas turbine for aircraft



Myth 3:

“Efficiency of gas turbines cannot be substantially improved”

*Images taken from J. Sieber: „Aero Engine Roadmap 2050”

”We took something so old and simple as a one-stage gear box and that resulted in a fuel burn reduction of 16 %.”



Myth 3:


*Images taken from S. Kaiser, M. Nickl: „Investigations of the Synergy of Composite Cycle and Intercooled Recuperation”

**Images taken from S. Kaiser et al.: “A Composite Cycle Engine Concept for Year 2050”

Improvements of 8 % to 10 % in fuel burn

However:

CO2 and NOx emissions increase significantly



Myth 3:


*Images taken from H. Kayadelen: „Thermoenvironomic evaluation of simple, intercooled, STIG, and ISTIG cycles”

60 % NOx reduction



Distributed electric propulsion:

Increasing𝐶𝐿

𝐶𝐷by utilizing the scale behavior of electric motors

2 propellers

Conventional twin-engine

𝑁 propellers

Wing distributed electrical propulsion

*Images taken from M. Hepperle (2016)

** Data source: G. Atanasov (2018)

1 engine

per wing

2 engine

per wing

3 engines

per wing

𝐶𝐿𝐶𝐷

~ 23

𝐶𝐿𝐶𝐷

~ 16



A consequence of VTOLs:

New operation concepts

*Images taken Uber Elevate



Myth 4:

“Urban air mobility will solve urban congestion problems”

*Following the Keynote of P. Plötner: „Future Perspectives of Aviation for Urban and Regional Mobility” (2019)

Example: Munich Metropolitan Area

4.5 million inhabitants → 8.7 million trips/d

1% of trips with UAM: 87.0000 trips/d

10% of trips with UAM: 870.000 trips/d

Comparison:

MUC: 1.000 aircraft moves/d



Myth 4:



Capacity:

> 1000 landings/h (12 pads, 23 s/landing)


> 24 landings/h per pad (60 s/landing)

Example: Munich

Operating hours (06:00 – 23:00)

1 % of trips with UAM:

> 61 large vertiports

> 126 medium vertiports

> 213 small vertiports







Myth 4:



Capacity:



> 24 landings/h per pad (60 s/landing)

Example: Munich

Operating hours (06:00 – 23:00)









Public transport in Munich:

> 100 underground stations

> 150 suburban stations

> 173 tram stations

> 1006 bus stops

Share:

> 24 % in Munich City

> 11 % in Munich Suburbs



Myth 5:

“Electric aircraft is silent”

*Following the Keynote of J. Delfs: „E2Flight = silent ?” (2019)

• FFT analysis of EXTRA330 overflight reveals

that the electric version has significantly lower

noise emissions

• Probably due to less torque ripple than ICE

Frequency [Hz]



Myth 5:





Myth 5:



• Many additional noise sources beyond the

propulsion unit

• Solely replacing the gas-turbine of a turbo-fan

with an electric motor will not have a hearable

effect since other noise sources prevail



Myth 5:



*Image courtesy of NASA and Airbus Group

The aircraft design space that is available due

to hybrid-electric propulsion could be used to

build low noise emission aircraft



Agenda



III. Should we do invest into (hybrid-)electric?



A comparison of designs based on electric propulsion

~ 10%

Mission distance: ~ 800 nm*Taken from M.Strack: „Conceptual Design

Assessment of Advanced Hybrid Electric

Turboprop Aircraft Configurations“ (2018)



Advantages of (hybrid) electric propulsion:

Mission Profile

Typical mission profile

𝜂𝑇~ 40 %

𝜂𝐸~ 95 %

A320/B737 Design Range

A320/B737 Flight Usage

Design Range of PHA2

*Plot taken from hastydata.worldpress.com

**Data from: https://openflights.org/data.html



Do we need superconductivity for that?

R =v

g ∙ SFC

CLCD

lnmfuel +mempt

mempt

Breguet-Formula (Turbo-Electric):

Component Warm Cold

Electric

Machines

10 kW/kg 25 kW/kg

Power Electronics 30 kW/kg 60 kW/kg

Cables 40 kW/kg 100 kW/kg

Educated guess on power density

(incl. heat exchangers):

SP2000D SG10000

warm:

~3 kW/kg

cold:

~7 kW/kg

~ 10% Extra Range

~ 10% less SFC



Myth 6:

Superconductivity is an extraordinary complex technology

*Image of a PW gas turbine engine, taken from:https://www.americanmachinist.com/news/pratt-whitney-machinists-union-settle-five-year-deal

Combustion Chamber

@ 1600 degC

Airgap

2 mm clearance

on 2 m diameter

Multi shaft

design

Complex fuel pipes and

injection control

Brushless-DC Motor Aircraft Turbo-Fan PropulsorSiemens eAir

10 MW HTS Design



Last Slides – Key Messages: We don’t have to wait long

We will have empirical evidence soon!



Last Slides

Invest in Lithium, because the future of flight is electric!



Dr. Mykhaylo Filipenko

Head of center of competence electrical machines 1

Siemens Corporate Technology

Next47 - eAircraft

CT CTP AIR AS ELM1

E-mail:

[email protected]

Internet

siemens.com/corporate-technology

mailto:[email protected]

http://siemens.com/corporate-technology

electric and hybrid-electric aircraft · 2019. 8. 7. · keep a320 design + “replace turbine with...

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